Adding sound to Children’s Museum exhibits

Believe it or not, the local Children’s Museum staff was happy that [Bill Porter] left this mess of wires and equipment in one of their offices. It makes up an ambient sound system for a couple of their exhibits. A movie without sound just doesn’t fully entertain, and the same can be said for these exhibits. The ambient sound that goes with a boat room, and a hospital room in the Museum really helps to snag your attention. And [Bill’s] material cost came in at just over $200 for both rooms.

He started off by purchasing a speaker, amp, and MP3 breakout board (SparkFun). The speaker mounts in one of the ceiling tiles, with the wire running to a different room where the audio equipment is housed. There were a couple of problems with this; the museum staff forgot to turn on the system, and for all of its expense this only provided one room with audio. Bill figured that since only one speaker was being used he could make an audio file with a different clip on the left and right channel, then feed them to different rooms. He also added that programmable timer so the sounds will turn themselves on and off.

This isn’t the first time we’ve seen hacks end up as museum pieces. Check out this other project that rigs up some interactive telephones.

Im not sure i understand complication why not do away with the micro controller and just attach a £3 mp3 player from china straight to the rca input of the amp load in the sounds and loop, could have replaced to amps with a second hand multi zone amp for a few ££ and tied it all in one package with multiple zones its future proofed for more exhibits.

I’m sure he learned a lot building the project and I also enjoy helping museums out when I can with my limited talents and resources. I would only add in the advice that the thrift store is your friend and as soundshark noted, the left/right pan can be done with cheaper sources. It is pretty easy to fit a mp3 player “one shot” style under an arcade button and have a keybox to access. You can even put small soundbites in and set it to shuffle for a different experience every time :) Thanks for helping out a museum :)

I decided against a cheap mp3 player to guarantee continued operation. The dollar store mp3 player don’t have a loop function, and if they did, would not automatically start playing upon power up.

I didn’t have two amps, just one. I turned a stereo amp into a “2 zone” amp with the left and right channels. The cost (even in multiple) was still better then any multi channel amp I could fine, and I didn’t want to add to the confusion with a further complicated surround sound amp with each of the 6 channels going to another room.

Yeah the surround panning doesn’t come out nearly as clean as the ol LR. Good on you for maximizing what ya had :) Target often has lil hanna montana or hello kitty mp3 players on sale for 10-20 bux -might be a helpful source. They also sell little light up mp3 amp speakers in the stocking stuffer POS. They light up and run on batts or wall wart (inc). Cheers

Each mono 3.5″ to one MP3 player, connecting to one of the Amp’s RCA’s (one for the left channel, the other to the right channel).

Done.

—–

Some cheap MP3 players do have repeat and do play on power on; ipod nano knock offs come to mind (DX). Even if they didn’t play on power on, it doesn’t hurt the staff to press the play buttons when they turn the other equipment on).

Like I said, I personally tested 3 cheap MP3 players before deciding. Only one had loop, and it would not play upon power up. If you have personally tested and verified a cheap mp3 player will do both, please link it.

And the staff couldn’t even handle turning it on. It’s mostly manned by a quickly rotating pool of volunteers, so knowledge doesn’t spread well between them. A requirement of the system was to be completely automatic and reliable.

I have tested the $40 MP3 trigger board for almost a hundred hours of use. I knew it would do exactly what I wanted. That’s why I finally choose it for this project.

If your design works for you then thats what matters i suppose everyone has a way they like to do things everything i do is most likely wrong “well that’s what the wife keeps telling me” but im not dead yet :) and iv not set fire to anything in ages so it must work :)

Man that thing looks like a piece of crap, but hey it works (independent of staff too), so its a nice hack, and since he did all the work himself, bought all the equipment and donated it to the museum its also a very generous gesture.

Both as a professional engineer, and as someone who has donated work and projects to non-profits, I’m a little taken aback. It’s important that the project be supportable in the future, even if the implementor gets his by a bus. It needs to be stable and not susceptible to damage from shocks and knocks. An extra project box and some zip-ties, at a minimum, would not have gone amiss here. That and a three-ring binder with complete documentation, for the project of course.

Plaid, as a professional engineer, you should know better then to jump to conclusions. There is a few new pages in the museum’s master binder, not to mention the address to my blog post that documents the system.

If you RTFA, you would have read that most of the messiness on that shelf is due to train controllers I had no part of. The few wires leading in and out of the amp are bundled up and secured. The single mp3trigger board is secured to the stiff card board box with standoffs. I’ll argue it provides equal protection as a more expensive plastic enclosure. I have seen decade old exhibits using cardboard boxes to cover electronics with no issues.

The picture that hackaday chose, really gives the wrong impression. At first glance it’s WTF is all that. Looking at the site it becomes apparent that the mess is other stuff not related with the hack aside from the timer which is what is being shown in that shot. Nice thinking about using an stereo amp in that fashion. I might have gone a different route for the board enclosure but hey a box works.

The truth is the box was an after thought. I tired using cheap mp3 players first, which wouldn’t need a box. When I settled on the mp3trigger and needed a box, it was wait a week for one to come via mail at more cost, or make something I had work.